My friends mom was adopted also in the 40's and as you said Sue, the birth mother was well supported, but the father was not mentioned.
She traced her birth mother and subsequently visited the street where she was born and met some neighbours who remembered her mom and knew about her adoption.
One of the neighbours invited her in and in the conversation that followed, asked if she knew her dad. Turned out that this neighbour was the sister of her father, her aunt, and she did get to meet her dad. Her mom met her once, but then did not want to stay in touch, but she has a good relationship with herdad, who didn't want her adopted, but wasn't given any say in the matter. Such a shame, he was a lovely man, who never married or had children.
Sue